1. Field of the Invention
The present invention relates to a method for conjecturing the effective width and effective length of a gate. In particular, the present invention relates to a method for conjecturing the effective width and effective length of a gate using an optimal width error and length error and determining an intrinsic gate channel capacitance and an edge capacitance of a design gate by calculation.
2. Description of the Prior Art
MOSFET is an important semiconductor element, usually made from the standard semiconductor process. When the standard semiconductor process is used, every part of the semiconductor element, such as a source, a drain and a gate, is gradually formed in accordance with a pre-determined specification. The effective gate width (Weff) as well as the effective gate length (Leff) which are highly associated with the electrical properties of the MOSFET need checking carefully because the effective gate width and the effective gate length have profound influence on the element performance and the development of the process.
Although each part of the semiconductor element, such as the gate, is gradually formed in accordance with a pre-determined specification, however, due to the process variation, the gate size, or the effective gate width and the effective gate length to say, is not quiet the same as the expected specification. Strictly speaking, the electrical properties' highly-associated effective gate width and effective gate length are more crucial than the physical gate width and physical gate length because they influence on the element performance and the development of the process much more profoundly.
The current method used to determine the gate width and the gate length is by TEM. However, this is not a flawless way to do it. In one aspect, the results are not reliable due to the limited sampling and checked by naked eyes. In another aspect, the results can merely reflect the physical width and the physical length of the gate. It none the less reveals nothing about the effective gate width and the effective gate length which are practically associated with the electrical properties.
It is a shame that there is no current and useful way to determine an effective width and an effective length of a gate. Accordingly, to obtain a way to determine an effective width and an effective length of a gate is critical in this field.